Bone plate system for hand fractures and other small bones

ABSTRACT

A bone plate system for the internal fixation of metacarpal and phalanx fractures of the hand is provided. The plates are structured to permit independent reconfiguration of holes of the plates relative to a longitudinal axis and are configured to orient fasteners to interdigitate with holes displaced along the longitudinal axis. The plates are very thin, and a locking screw with a low profile head design is provided for use therewith.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates broadly to surgical devices and methods for theinternal fixation of fractured bones, and more particularly, to boneplates and fasteners.

2. State of the Art

Metacarpal fractures are the most common fracture affecting the hand,accounting for about 48% of hand injuries and 12% of all types offractures. Phalangeal fractures account for about 40% of hand injuriesand 10% of all fractures. Displaced metacarpal and phalangeal fracturesshould be treated with open reduction and internal fixation with screwsand very small bone plates.

Bone plate systems for hand fractures are currently available in thesmall sizes required for placement on metacarpal and phalangeal bones.For example, the Stryker Profyle Small Bone Plating System isspecifically designed for fractures of the metacarpal and phalangealbones. The system includes a set of small plates in several shapesincludes straight, T-shaped, L-shaped, and ladder configuration withparallel rails and rungs extending across the rails connecting thelocations of various fixation holes. By way of another example, theSynthes Compact Hand system includes straight, T-shaped, and Y-shapedplates for the fixation of fractures of the hand. The plates in thesystem can be bent in an attempt to approximate the contour of the bone.In order to bend a plate, a pair of pliers are used on opposing sides ofthe portion intended to be bent, or two rods are threadably coupleddirectly into a limited number of round threaded holes in the plate andforce is applied to the rods to bend the plate. In either method, theplate is bent off the bone through trial and error. In addition, theplates may be trimmed to length and then subsequently deburred, alsowhile off the bone to permit the cutting pliers proper access to theplate.

SUMMARY OF THE INVENTION

A bone plate system for the internal fixation of small bones, such asmetacarpal and phalangeal bones of the hand, is provided. Each plateincludes a straight rail with a longitudinal axis. The rail includes alinear arrangement of ring-shaped screw hole boundaries, with adjacentboundaries interconnected by a web having a width and a thickness. Eachboundary defines a screw hole for receiving a screw. Each screw hole maybe any one of a locking screw hole, a non-locking screw hole, and anelongated hole. In various embodiments one or more extensions extendsnon-axially from the rail. The extensions each include one or more screwhole boundaries, each boundary including a screw hole and linearlyconnected to the rail or another boundary by a web.

Preferred shapes for plates of the system, to accommodate the bones ofthe hand, include a straight plate, a T-shaped plate, a Y-shaped plate,a plate having a Y-shape at one end and a T-shape at its opposite end (aTY-shaped plate), and a ‘web’ plate having one or more extensions, eachextension with one screw hole boundary and extending from the locationof a hole in the rail of the plate. The arms of the Y-shaped plate andTY-shaped plate form a net or cage along the shaft of a bone for highenergy or segmental bone loss applications. This can be accomplished bybringing in the extensions along the bone shaft and leaving themunfilled. In addition, the extensions of the web plate are staggeredsuch that the trajectories of the axes of the holes in the extensions donot intersect the trajectories of the axes of the holes in the rail.

The plates are reconfigurable in shape, even while the plate is locatedon the bone. The plates are preferably provided pre-assembled withguides at any one of, and preferably each of, the threaded holes. Plateshaping tools may be attached to the guides and/or plate while the plateis located on the bone to effect alteration of the plate shape in aneffective and precise manner. In addition, the guides can be used to aiddrilling holes for fasteners to couple the plate to bone. The tools aredesigned such that a drill and K-wires can be inserted through theguides while the tools are coupled to the guides. Further, the plateshaping tools at the guides and/or pliers directly on the plate can beused to repeatedly stress a web location and purposefully cause a cleanbreak to alter the size and/or shape of a plate to better accommodatethe anatomy.

The boundaries of the plates surrounding the screw holes are very thin,and a small locking screw with a low profile head design is provided foruse therewith. The locking screw has a socket with a flat bottom recessthat optimizes the material thickness between the socket and a lowersurface of the head to provide sufficient driver engagement withoutreducing the torsional strength of the head to shank attachment relativeto screws designed for larger plates.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a straight plate according to the system of theinvention.

FIG. 2 is a side elevation of the straight plate of FIG. 1.

FIG. 3 is an isometric view of the straight plate of FIG. 1, shown withguides preassembled within the locking screw holes of the plate.

FIG. 4 is an isometric view of a guide for use in the system of theinvention.

FIG. 5 is a side elevation of a T-shaped plate according to the systemof the invention.

FIG. 6 is an isometric view of the T-shaped plate of FIG. 5.

FIG. 7 is an end view of the T-shaped plate of FIG. 5.

FIG. 8 is a view similar to FIG. 6, shown with guides pre-assembledwithin the locking screw holes of the plate.

FIG. 9 is a side elevation of a Y-shaped plate according to the systemof the invention.

FIG. 10 is an isometric view of the Y-shaped plate of FIG. 9.

FIG. 11 is an end view of the Y-shaped plate of FIG. 9.

FIG. 12 is a view similar to FIG. 9, shown with guides pre-assembledwithin the locking screw holes of the plate.

FIG. 13 is a side elevation of a TY-shaped plate according to the systemof the invention.

FIG. 14 is an isometric view of the TY-shaped plate of FIG. 13.

FIG. 15 is a first end view of the TY-shaped plate of FIG. 13.

FIG. 16 is a second end view of the TY-shaped plate of FIG. 13.

FIG. 17 is a view similar to FIG. 13, shown with guides pre-assembledwithin the locking screw holes of the plate.

FIG. 18 is a side elevation of a web plate according to the system ofthe invention.

FIG. 19 is a plan view of the web plate of FIG. 18.

FIG. 20 is an isometric view of the web plate of FIG. 18.

FIG. 21 is an end view of the web plate of FIG. 18.

FIG. 22 is a plan view of an alternate web plate, shown with guidespre-assembled within the locking screw holes of the plate.

FIG. 23 is a side elevation of a bending tool for manipulating a platevia the guides preassembled to the plate.

FIG. 24 is a side elevation of the tool of FIG. 23, shown rotated 90°relative thereto.

FIG. 25 illustrates a method of assembling a T-shaped plate to bone withthe tools of FIG. 23.

FIG. 26 illustrates a method a assembling a web plate to bone with thetools of FIG. 23.

FIG. 27 is a top view of the method of FIG. 26.

FIG. 28 illustrates the web plate shaped to the bone.

FIG. 29 is a perspective view of a locking screw according to theinvention.

FIG. 30 is a broken section view of the locking screw of FIG. 29.

FIG. 31 is a perspective view of a non-locking screw according to theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A bone plate system for the internal fixation of small bones, such asmetacarpal and phalangeal bones of the hand, is provided and includesbone plates 10 (FIGS. 1 through 3), 110 (FIGS. 5 through 8), 210 (FIGS.9 through 12), 310 (FIGS. 13 through 17), and 410 (FIGS. 18 through 22).

Referring to FIGS. 1 through 3, bone plate 10 is a plate with a straightrail 12 defining a longitudinal axis A of the plate. The rail 12includes a linear arrangement of ring-shaped screw hole boundaries 14,with adjacent boundaries interconnected by respective webs 16. The webs16 each have a length L of 1.77, a width W of 3.05 mm, and a thickness Tis 1.24 mm. The webs 16 have a lower surface 26 which is recessedrelative to the lower bone contacting surfaces 28 of adjacentboundaries. Each boundary 14 defines a screw hole 18 a, 18 b forreceiving a screw. The screw holes are either locking screw holes 18 aor elongated non-locking screw holes 18 b. Locking screw holes 18 ahaving internal threads 20 for engaging the threads at the head of alocking screw 620 (FIG. 29) or for receiving a guide 30 (FIG. 4), asdiscussed in more detailed below. The center-center distance C foradjacent locking screw holes is 7.42 mm. Screw holes 18 b are dynamiccompression plate (DCP) holes each with a respective upper recess 22 forreceiving the convex lower surface of a non-locking multidirectionalscrew 640 (FIG. 31), as also discussed below. The locking and DCP screwholes 18 a, 18 b may be symmetrically or asymmetrically arranged alongthe length of the rail. An embodiment of the plate 10 has a length of 90mm which is ideal for placement on the metacarpal bones.

Referring generally to FIGS. 1, 3 and 4, the threaded locking screwholes 18 a are each preferably preassembled with a guide 30. The guide30 has a cylindrical upper body 30 a, a threaded lower portion 30 b forengaging locking screw holes 18 a, a circumferential lip 30 b betweenthe upper and lower portions 30 a, 30 b that seats on the upper platesurface of a screw hole boundary 14, a bore 30 d and a driver engagementstructure 30 e, e.g., inner corners. As described in co-owned US Pub.Nos. 20060149250A1, 20060161158A1, 20070233111A1, which are herebyincorporated by reference herein in their entireties, and discussedfurther herein below, the guides 30 and associated tools 500 (alsodiscussed below with respect to FIGS. 23 through 27) facilitate (i)bending the plate while the plate is positioned on the bone, (ii)directing a drill through the threaded holes along the fixed axis of thehelical thread without necessitating assembly of a separate drill guideduring the surgical procedure, and (iii) repeated stressing of the platealong the web between adjacent guides to cause controlled removal of aportion of the plate. In view of point (iii), plate 10 and all plates ofthe system, can be readily shortened in length or otherwise modified inshape to accommodate a particular bone fracture, bone feature, orindividual patient anatomy.

Referring to FIGS. 5 through 8, bone plate 110 is generally T-shaped,comprising a straight rail 112, substantially similar to rail 12, and atransverse portion 114 at one end of the rail. The rail 112 includes alinear arrangement of ring-shaped screw hole boundaries 118 definingscrew holes, described below, with adjacent boundaries connected byrespective webs 122. The webs 122 of the rail 112 each have a length L₁of 1.77 mm, a width W₁ of 3.05 mm, and a thickness T₁ of 1.24 mm. Thetransverse portion 114 includes two oppositely-directed extensions 124a, 124 b at one end of the rail. The extensions 124 a, 124 b alsoinclude screw hole boundaries 126, with adjacent boundaries connected byrespective webs 128. Webs 128 each have a length L₂ of 1.48 mm, a widthW₂ of 2.16 mm, and a thickness T₂ of 1.4 mm. The larger dimensions ofthe webs 122 of the rail 112 relative to the webs 128 of the extensions124 a, 124 b provide a rail with increased torsional stiffness relativeto the extensions. This allows the extensions 124 a, 124 b to berelatively easily shaped to the bone (as described below) withoutinadvertently imparting a twist to the straight rail 112. As a result,the surgeon can more freely manipulate the extensions in bending withoutconcern for deformation of the rail. The lower bone contacting surfaces132 of the boundaries along the extensions 124 a, 124 b are preferablyarranged along a 120°±20° curve (transverse to the longitudinal axis A)at a radius of 13.3 mm to conform to the shape of the bone on which theplate is seated.

An embodiment of the T-shaped plate 110 has an overall length of 73.8mm, a transverse dimension Dt from the side of one extension to the sideof the other extension of 27.6 mm, and a vertical dimension Dv definedbetween the rail at the center of the extensions and the ends of theextensions of 10.5 mm. In the embodiment shown, the rail 112 includesten threaded locking screw holes 120 a, and one non-locking oblong (DCP)screw hole 120 b for dynamic compression of a fracture during fastenerinsertion through the hole. The DCP screw hole 120 b is positioned withseven locking screw holes 120 a on side and three locking screw holes120 a on the other side thereof. The extensions 124 a, 124 b eachinclude two locking screw holes 120 a. The T-shaped plate 110 is sizedand shaped for metacarpal fractures. As shown in FIG. 8, the threadedlocking screw holes 120 a of the plate are preferably pre-assembled withguides 30.

Turning now to FIGS. 9 through 12, bone plate 210 is a Y-shaped plated,having a straight rail 212, and two extensions 216 a, 216 b branched offone end of the rail. The rail 212 is substantially similar to rail 112,with webs 222 having the same web dimensions as 122, but rail 212 may beof different length and may include a different number of screw holeboundaries 218, and have a different number of threaded screw holes andDCP holes. The extensions 216 a, 216 b have webs 226 with the samedimensional properties as the extensions of the T-shaped plate. Theextensions 216 a, 216 b include respective first portions 234 a, 234 bangled relative to each other, and second portions 236 a, 236 b parallelto each other. The first portions 234 a, 234 b are preferably angledrelative to each other in the plane of the rail 212 at an angle α,wherein α=60°±10°. The relatively angled first portions 234 a, 234 bprovide relief to a tendon attachment point. The parallel secondportions 236 a, 236 b extend alongside the bone to saddle or buttressthe condyles of either the head or base of the long bones of the hand orfoot, e.g., metacarpals, phalanges and metatarsals. The parallel secondportions 236 a, 236 b also permit placement of screw hole boundarieslaterally on either side of tendon attachments located on the dorsalside of the head or base of the long bones of the hand or foot. Thelower bone contacting surfaces 238 a, 238 b of the boundaries of theextensions 216 a, 216 b are preferably arranged along a 60°±5° curve(transverse to the longitudinal axis A) at a radius of 15.2 mm. In oneembodiment, the plate 210 has an overall length of 71.9 mm, a transversedimension Dt from the side of one extension to the side of the otherextension of 19.5 mm, and a vertical dimension Dv defined between therail at the center of the extensions and the ends of the extensions of4.5 mm. In the embodiment shown, the extensions 216 a, 216 b eachinclude three screw hole boundaries 218, with the first portions 234 a,234 b defined from respective first and second screw hole boundaries,and the second portions 236 a, 236 b defined from respective second tothird screw hole boundaries to engage the condyles of the bone. As shownin FIG. 12, the threaded holes of the plate are preferably pre-assembledwith guides 30.

Referring now to FIGS. 13 through 17, bone plate 310 has a straight rail312, a transverse portion defined by two opposing extensions 314 a, 314b at one end forming a T-shape, and two extensions 316 a, 316 b in aY-shape configuration at its opposite end; plate 310 is referred to as aTY-shaped plate.

In the embodiment shown, the T-shape portion is generally similar toT-shape plate 110, but is distinguished by each extension 314 a, 314 bhaving a single screw hole boundary, each with a locking screw hole 320a on each side of the rail 312. The transverse dimension Dt1 from theside of one extension 314 a to the side of the other extension 314 b is19.5 mm, and the overall vertical dimension Dv1 defined between the rail312 at the center of the extensions and the ends of the extensions of4.7 mm. The lower bone contacting surfaces 338 of the boundaries of theextensions 314 a, 314 b are preferably arranged along a 60°±5° curve(transverse to the longitudinal axis A) at a radius of 13.9 mm.

The Y-shaped portion is generally similar to Y-shaped plate 210, but isdistinguished by each extension 316, 316 b having four screw holeboundaries, each with a threaded screw hole 320 a, with three screwholes in each of the parallel second portions 322 a, 322 b. Thetransverse dimension Dt2 from the side of one extension 322 a to theside of the other extension 322 b is 19.5 mm, and the overall verticaldimension Dv2 between the rail 312 at the center of the extensions 316a, 316 b and the ends of the extensions is 4.5 mm. The lower bonecontacting surfaces 340 of the boundaries of the extensions are alsopreferably arranged along a 60°±5° curve (transverse to the longitudinalaxis A) at a radius of 15.2 mm.

The webs 322 of the rail 312 each have a length of 1.77 mm, a width of3.05 mm, and a thickness of 1.24 mm. The webs of the extensions eachhave a length of 1.48 mm, a width W₂ of 2.16 mm, and a thickness of 1.4mm. Thus, the webs of the rail are stiffer than the webs of theextensions. The plate 310 has an overall length of 55.5 mm. TheTY-shaped plate is preferably sized and shaped to conform to the bonefor metacarpal fractures. As shown in FIG. 17, the locking screw holesin the plate are preferably pre-assembled with guides 30.

Turning now to FIGS. 18 through 22, bone plate 410 includes a straightrail 412 with screw hole boundaries 418, and a plurality of extensions424 extending from the screw hole boundaries at each side of the rail.The extensions 424 each include a single screw hole boundary 418. Thewebs 422 of the rail 412 each have a length L₁ of 1.77 mm, a width W₁ of3.05 mm, and a thickness of 1.24 mm. Webs 428 of each extension have alength L₂ of 1.48 mm, a width W₂ of 2.16 mm, and a thickness of 1.4 mm.In one embodiment of the plate 410, the terminal boundaries of the railare each provided with two extensions in (opposing) Y-shapedconfigurations 432 a, 432 b, and a relatively longitudinally centralboundary is provided with two extensions 424 a, 424 b in a diagonallyopposed relationship. The remaining boundaries include only a single webat an oblique angle relative to the longitudinal axis A. In theembodiment shown in FIGS. 18 through 21, along a first side of the platefour adjacent extensions 424 are in a parallel relationship,non-orthogonally angled relative to the longitudinal axis A in the planeof the rail at an angle β, wherein β=60°, and three adjacent extensionsare in a parallel relationship, at an opposite angle −β relative to thelongitudinal axis A. Along a second side of the plate, three adjacentextensions are in a parallel relationship, non-orthogonally angled at βin the plane of the rail relative to the longitudinal axis A, and threeadjacent extensions are in a parallel relationship at an opposite angle−β relative to the longitudinal axis A.

Referring to FIG. 21, the transverse dimension Dt from the side of anextension on one side of the rail to an extension on the other side ofthe rail is 17.4 mm, and the overall vertical dimension Dv between therail at the center of the extensions and the ends of the extensions of4.5 mm. The lower bone contacting surfaces 440 of the boundaries of theextensions are also preferably arranged along a 60°±5° curve (transverseto the longitudinal axis A) at a radius of 11 mm. As seen best in FIGS.19 and 20, the arrangement of the extensions 424 relative to the rail412 provides a staggered arrangement of threaded screw holes 420 suchthat the fixed angle trajectory of the axes of the holes in theextensions 424 do not intersect the trajectories of the axes of thethreaded screw holes in the rail 412. The plate 410, referred to as aweb plate is both laterally and longitudinally asymmetrical, with higherplate hole density at the ends of the plate and along one side of theplate. The asymmetrical shape of the web plate allows a surgeon toselect to which side of the straight rail (left or right) a largerconcentration of screw hole boundaries will be provided on the bone byrotating the plate about an axis normal to the top surface of the plate.(FIG. 22 shows a similar plate oriented to provide a higherconcentration of plate holes along an opposite side relative to theplate in FIG. 19). The web plate 410 also provides a net or cage alongthe bone shaft for high energy or segmental bone loss application. Thiscan be accomplished by bringing the extensions in along the bone andleaving them unfilled with bone graft. The web plate 410 is preferablysized and shaped to conform to the bone for metacarpal fractures, and isdesigned to maintain the length of a bone even where there is extensivebone loss due to injury. The plate of FIGS. 18 through 21 has a lengthof 79 mm. As shown in FIG. 22, the plate may have a shorter rail withfewer screw hole boundaries and thus a shorter length. Similarly, theplate may have a longer rail with more screw hole boundaries and thus alonger length. As also seen in FIG. 22, the locking screw holes in theweb plate 410 are preferably pre-assembled with guides 30.

As discussed above, each of the plates is preferably pre-assembled withguides 30. Referring to FIGS. 23 and 24, plate bending tools 500 (onesuch tool is shown, however the tools are generally used in pairs) maybe attached to the guides and/or plate while the plate is located on oroff the bone to effect alteration of the plate shape in an effective andprecise manner. Each bending tool 500 includes a first end 552, a secondend 554, and an L-shaped handle 556 extending therebetween. The firstend 552 defines a longitudinal axis A₁, the second end defines alongitudinal axis A₂, and axes A₁ and A₂ are orthogonal relative to eachother. The only distinction between the two tools of a pair of tools isthat the handles 556 of a pair extend in opposite directions relative toeach other.

Referring to FIGS. 23, 24 and 25, the first end 552 defines a socket 560sized to closely receive the tip 30 a of a guide 30, and means forrotationally fixing the first end 552 relative to a portion of the boneplate, such as the webs 122, 128 of T-shaped plate 110, although thetools work the same with any of the plates. In a preferred embodiment,the means for rotationally fixing the first end relative to the boneplate are two feet 562, 564 that straddle the webs 122, 128 of the plate110. The two feet 562, 564 include curved inner surfaces 566 that seatabout the radiused screw hole boundaries 118, 126 of the plate toquickly and easily align the tool 500 on a plate. The feet 562, 564 eachhave a toe end 574 for abutting the web, e.g., 122, at a fulcrumlocation, and a heel end 576 for applying force to a screw hole boundary118. Then, rotation of the second end 554 of the handle 556 relative tothe plate 110 imparts a force to the plate that effects bending of theplate in the plane of the plate about the fulcrum. The second end 554 ofthe tool defines a bore 580 with a central longitudinal axis A_(B)oriented an oblique angle relative to the longitudinal axis A₂ of thesecond end 554. The angle φ between A₂ and A_(B) is 160°±15°. The bore580 is sized in diameter to be closely received over the tip 30 a of theguide 30. The bore 580 preferably includes an enlarged lower portion 582for receiving the shoulder portion 30 c of the guide 30 so that the toolcan seat flush on the upper surface of the plate. The bore 30 d of theguide 30 is also sized to receive a drill guide 600 (for drilling ascrew hole through the guide) and a K-wire 610 (for temporary fixationof the plate through the guide).

Referring to FIGS. 26 and 27, a web plate 410 is shown with guides 30preassembled thereto. The web plate 410 has been shortened from aninitial length through the use of the tools. That is, tools 500 havebeen coupled to guides 30 on either side of the web 422 a which is to bea new terminus of the plate, and the tools are operated to repeatedlyreverse bend the plate at the web 422 a in the longitudinal directionuntil the plate separates at the web to reduce the length of the plateand provide a new plate terminus 450. Such ability to remove and methodof removing a portion of a plate applies to all plates of the system andall portions of the plates, including any extension thereof, or portionsof extensions thereof.

The plate 410 is provisionally coupled to a small long bone such as aphalangeal bone 612 (or metacarpal bone) with screws 620 insertedthrough an end locking screw hole 420 a and the locking screw hole 420 bof the new terminus 450 thereof and into the bone 612.

The extensions 424 of the plate 410 are shaped to the bone 612 with thetools 500. The bores 580 of respective tools 500 are positioned over thebodies 30 a of the guides 30 and appropriate relative force is appliedto re-orient the screw hole boundaries 418 as necessary to (i) seat thebone contacting surface of the plate close to the underlying bone and/or(ii) orient the locking screw hole axes such that locking screwsinserted through the locking screw holes will be oriented in a desireddirection so as to engage desired bone and bone fragments withoutinterference with other locking screws. With the bending tools 500coupled to the guides and plate in the described manner, the plate 410may be bent along any web in concave and convex directions(longitudinally) and rotationally along an axis of any web (in torsion).The screw hole boundary of each extension can be oriented independentlyof all other screw hole boundaries. Once a web has been bent to orient ascrew hole boundary 418, a K-wire may be inserted through the bores ofthe tool 500 and guide 40 to temporarily fix the location of theboundary (and overcome any springback in the plate)(as shown in FIG.25), or a hole may be drilled through the bores of the tool 500 andguide 30 with drill 600 for receiving a locking screw. The bore 580 ofthe tool 500 is sized so that the tool may be withdrawn from over theK-wire, guide and/or drill, while leaving such components in placerelative to the plate. Once the hole is drilled, the guide 30 may beremoved and a locking screw 620 may be inserted. FIG. 28 illustrates theplate 410 fully shaped over the bone 612 and fragments, with guidesremoved. It should be appreciated that additional locking screws 620 maybe inserted through the plate 410 and into the bone throughout the plateshaping procedure.

While the above plates have dimensions particularly suitable formetacarpal application, the shapes, structures, and benefits or suchplate are equally applicable to treatment of fractures of smaller longbones such as the phalanges. However, it is anticipated that the plateswill be scaled down in size (with appropriately scaled dimensions forplate holes, rail webs, extension webs, lengths, etc.) for use on suchsmaller bones. An appropriate scaling for phalangeal application wouldbe plates seventy percent of the size of the plates described above formetacarpal use.

Turning now to FIGS. 29 and 30, a locking screw 620 is providedspecifically for use with thin scaled-down plates (approximately 1 mmthick) such as for treating phalangeal fractures. The locking screw 620is preferably made from cobalt chrome alloy. The locking screw 620includes a head 622 and shaft 624. The head has machine threads 625 thatextend about 1.0±0.1 mm of vertical distance of the head. The head 622also has a non-circular socket 626 with a flat bottom recess 628 thatoptimizes the material thickness T_(m) between the socket 626 and alower surface 630 of the head. The minimum material thickness T_(m) ispreferably 0.4±0.1 mm, and allows a socket 626 with sufficient driverengagement without reducing the torsional strength of the head to shaftattachment relative to screws for designed for larger plates. The abovefeatures provide a screw with a low profile head design but the strengthof a larger screw. The shaft 624 preferably has bone engaging threads632, but may optionally be smooth. The thin low profile of both theplate and the locking screw minimizes soft tissue irritation.

Referring to FIG. 31, a non-locking multidirectional screw 640 is alsoprovided for use in the non-locking holes of the plates of the system.The screw 640 is preferably made from titanium alloy. Screw 640 has anon-threaded head 642, preferably with a rounded lower surface 644, anda threaded shaft 646. Each of the locking and non-locking screws 620,640 may be provided in various lengths. In addition, all the holes ofthe various plates may be locking, non-locking, or in a differentlocking/non-locking arrangement than described above to receive thescrews 620, 640.

The plates of the system are uniquely shaped for fixation of most typesof metacarpal/phalanx fractures. The straight plate 10, T-shaped plate110, Y-shaped plate 210, TY-shaped plate 310, and web plate 410 provideall the shapes required for fixation of all fractures in such smallbones, and as a kit or system provide options for small long bonefixation that is not available in any other kit or system. Such shapesare each highly configurable through the shaping procedure describedherein so as to adaptable to individual patients and the uniquecircumstances of a given fracture. Further, by changing the length ofthe various plates (through reverse bending), the functional structuralaspects of the individual plates remains. In addition, given the highsymmetry in certain individual plates (each of the straight plate,T-shaped plate, Y-shaped plate, and TY-shaped plate are laterallysymmetrical), they are adapted for both left and right hand use.Moreover, the asymmetry of the web plate permits the surgeon toconcentrate fasteners to one side of bone, if required. Each of theplates of the present system may be formed from any one of numerousmaterials known in the art, including stainless steel, titanium, andtitanium alloy such as Ti-6Al-4V.

There have been described and illustrated herein embodiments of a systemfor treating small bone fractures, including bones of the metacarpalsand phalanges, and individual plates therefor. In addition, methods ofcustomizing the plates to various bones are described. While particularembodiments of the invention have been described, it is not intendedthat the invention be limited thereto, as it is intended that theinvention be as broad in scope as the art will allow and that thespecification be read likewise. By way of example, various dimensions ofthe plates sized for metacarpal application are provided, as well as ascaling factor for plates for smaller bones. While preferred dimensionsfor plates for such application are provided, it is appreciated thatvariations in dimension (e.g., ±ten percent) are permissible providedsuch variations do not cause the extensions to have a higher torsionalstiffness than the rail in the respective plates. It will therefore beappreciated by those skilled in the art that yet other modificationscould be made to the provided invention without deviating from itsspirit and scope as claimed.

What is claimed is:
 1. A fracture fixation kit for fixation of fracturesof small bones, including metacarpal and phalangeal bones, said kitcomprising: a) a straight plate consisting of a straight rail comprisingscrew hole boundaries connected by web elements of reduced thickness andwidth relative to said boundaries; b) a T-shaped plate consisting of astraight rail comprising screw hole boundaries connected by web elementsof reduced thickness and width relative to said boundaries, first andsecond ends, and a transverse extension at said first end; c) a Y-shapedplate consisting of a straight rail comprising screw hole boundariesconnected by web elements of reduced thickness and width relative tosaid boundaries, first and second ends, and a pair of extensions at saidfirst end, said pair of extensions having a portion angled relative toeach other at an angle between 50° and 70°; d) a TY-shaped plateconsisting of a straight rail comprising screw hole boundaries connectedby web elements of reduced thickness and width relative to saidboundaries, first and second ends, a transverse extension at said firstend, and a pair of extensions at said second end, said pair ofextensions at said second end being angled relative to each other at anangle between 50° and 70°; and e) a web plate consisting of a singlestraight rail having a longitudinal axis, said rail comprising firstscrew hole boundaries each with a respective central axis, said firstscrew hole boundaries connected by web elements of reduced thickness andwidth relative to said first screw hole boundaries, and an extensioncoupled to each first screw hole boundary of said rail, each extensionhaving at a free end thereof a second screw hole boundary each with acentral axis, wherein each second screw hole boundary has at most oneextension coupled thereto, and wherein said extensions are coupled inalternating arrangement on opposite sides of said rail so that centralaxes of said respective second screw hole boundaries of said extensionsinterdigitate with said central axes of said first screw holesboundaries of said rail, wherein each of said plates is sized to beplaced on a metacarpal or phalangeal bone for fracture fixation thereof.2. A kit according to claim 1, wherein: at least a plurality of screwhole boundaries of each of said plates includes threaded screw holes. 3.A kit according to claim 2, wherein: at least two of each of saidthreaded screw holes of each of said plates is pre-assembled withthreadably removable tubular guides.
 4. A kit according to claim 2,further comprising: a screw having a head portion and a shaft portion,said head portion having a non-circular socket with a flat bottomrecess, a lower surface, and external machine threads, wherein saidmachine threads extend about at most 1±0.1 mm of vertical distance ofsaid head portion, a minimum material thickness between said socket andsaid lower surface of said head portion is 0.4±0.1 mm, and said screw ismade from cobalt chromium alloy, said screw threadedly engagable in saidplurality of threaded screw holes.
 5. A kit according to claim 1,wherein: said transverse extension of said T-shaped plate, said pair ofextensions of said Y-shaped plate, said transverse extension and pair ofextensions of said TY-shaped plate, and said extensions of said webplate are each displaced out of plane relative to said straight rail ofsaid respective plates.
 6. A kit according to claim 1, wherein: saidtransverse extension of said T-shaped plate, said pair of extensions ofsaid Y-shaped plate, said transverse extension and pair of extensions ofsaid TY-shaped plate, and said extensions of said web plate eachcomprise at least one second screw hole boundary connected to saidrespective rail of said respective plate by a second web element, saidsecond web element having reduced torsional stiffness relative to eachof said web elements of said respective rail of said respective plate.7. A kit according to claim 1, wherein: said straight plate, saidT-shaped plate, said Y-shaped plate, and said TY-shaped plate are eachlaterally symmetrical.
 8. A plate according to claim 1, furthercomprising: a plurality of tubular guides pre-assembled in said threadedscrew holes.
 9. A plate for fixation of fractures of small bones,including metacarpal and phalangeal bones, said plate consisting of: a)a single straight rail having a longitudinal axis, a first end, a secondend, a first side at one lateral side of said longitudinal axisextending between said first and second ends, and a second side at theother lateral side of said longitudinal axis extending between saidfirst and second ends, said rail comprising first screw hole boundarieseach with a respective central axis, said first screw hole boundariesconnected by first web elements of reduced thickness and width relativeto said first screw hole boundaries; and b) an extension coupled to eachof said first screw hole boundaries of said rail, each extension definedby a second web element having at a free end thereof a second screw holeboundary each with a central axis, said second web elements of reducedthickness and width relative to said second screw hole boundaries,wherein at most one extension is coupled to each of said second screwhole boundaries, and wherein, between said first and second ends of saidrail, said extensions are coupled in an alternating arrangement onopposite sides of said rail to said first and second sides of said railat said first screw hole boundaries so that said central axes of saidsecond screw hole boundaries interdigitate with said central axes ofsaid first screw holes boundaries, and wherein each of said second screwhole boundaries can be reconfigured independently of the other secondscrew hole boundaries.
 10. A plate according to claim 9, wherein: saidsecond web elements have reduced torsional stiffness relative to saidfirst web elements.
 11. A plate according to claim 9, wherein: a greaternumber of extensions are coupled to screw hole boundaries of said railat said first side of said rail than at said second side of said rail.12. A plate according to claim 9, wherein: said first and second screwhole boundaries define screw holes, wherein said screw holes have adenser distribution toward said first and second ends relative to acenter of said longitudinal axis.
 13. A plate according to claim 12,wherein: said screw holes have a denser distribution along one lateralside of said plate relative to the other lateral side of said plate. 14.A plate according to claim 9, wherein: said first and second screw holeboundaries define screw holes, wherein said screw holes have a denserdistribution along one lateral side of said plate relative to the otherlateral side of said plate.
 15. A plate according to claim 9, wherein:along said first side of the plate, a first plurality of adjacentextensions are non-orthogonally angled at a first angle in a plane ofsaid rail in a parallel relationship relative to the longitudinal axis,and along said second side of the plate, a second plurality of adjacentextensions are angled at said first angle.
 16. A plate according toclaim 15, wherein: along said first side of said plate, a thirdplurality of adjacent extensions are in a parallel relationship witheach other and a second angle which is opposite said first anglerelative to the longitudinal axis, and along said second side of saidplate, a fourth plurality of adjacent extensions are in a parallelrelationship relative to each other at said second angle relative to thelongitudinal axis.
 17. A plate according to claim 9, wherein: saidextensions are pre-formed to define a concave bone contacting surface.18. A plate according to claim 9, wherein: said central axes of saidsecond screw hole boundaries are defined by screw threads.
 19. A plateaccording to claim 18, in combination with: a plurality of tubularguides pre-assembled relative to said screw threads of said second screwhole boundaries.
 20. A plate according to claim 9, wherein: said firstend includes two extensions arranged in a Y-shaped configurationrelative to said rail.
 21. A plate according to claim 20, wherein: saidsecond end includes two extensions arranged in a Y-shaped configurationrelative to said rail.
 22. A plate according to claim 9, wherein: saidthickness of said first web elements is measured in a direction parallelto a central axis of an adjacent first screw hole boundary attached tosaid first web elements, and said thickness of said second web elementsis measured in a direction parallel to a central axis of said secondscrew hole boundary.
 23. A plate for fixation of fractures of smallbones, including metacarpal and phalangeal bones, said plate consistingof: a) a single straight rail having a longitudinal axis, a first end, asecond end, a first side at one lateral side of said longitudinal axisextending between said first and second ends, and a second side at theother lateral side of said longitudinal axis extending between saidfirst and second ends, said rail comprising an alternating arrangementof first screw hole boundaries and web element, each first screw holeboundary having a respective central axis, and said web elements havinga reduced thickness and width relative to said first screw holeboundaries, wherein said thickness of said first web elements ismeasured through the plate in a direction parallel to a central axis ofan adjacent first screw hole boundary attached to said first webelements; and b) an extension coupled to each first screw hole boundaryof said rail, each extension having at a free end thereof a second screwhole boundary each with a central axis, said extension having a reducedwidth and thickness relative to said second screw boundary, wherein saidthickness of said extensions is measured through the plate in adirection parallel to a central axis of said second screw hole boundary,wherein at most one extension is coupled to each said second screw holeboundary, and wherein, between said first and second ends of said rail,said extensions are coupled in an alternating arrangement to said firstand second sides of said rail at said first screw hole boundaries sothat said central axes of said second screw hole boundariesinterdigitate with said central axes of said first screw holesboundaries of said rail, said plate sized for placement on a metacarpalor phalangeal bone for fracture fixation thereof.
 24. A plate accordingto claim 23, wherein: a greater number of extensions are coupled toscrew hole boundaries of said rail at said first side of said rail thanat said second side of said rail.
 25. A plate according to claim 23,wherein: said first and second screw hole boundaries define screw holes,wherein said screw holes have a denser distribution toward said firstand second ends relative to a center of said longitudinal axis.
 26. Aplate according to claim 25, wherein: said screw holes have a denserdistribution along one lateral side of said plate relative to the otherlateral side of said plate.
 27. A plate according to claim 23, wherein:said first and second screw hole boundaries define screw holes, whereinsaid screw holes have a denser distribution along one lateral side ofsaid plate relative to the other lateral side of said plate.
 28. A plateaccording to claim 23, wherein: along said first side of the plate, afirst plurality of adjacent extensions are non-orthogonally angled at afirst angle in a plane of said rail in a parallel relationship relativeto the longitudinal axis, and along said second side of the plate, asecond plurality of adjacent extensions are angled at said first angle.29. A plate according to claim 28, wherein: along said first side ofsaid plate, a third plurality of adjacent extensions are in a parallelrelationship with each other and a second angle which is opposite saidfirst angle relative to the longitudinal axis, and along said secondside of said plate, a fourth plurality of adjacent extensions are in aparallel relationship relative to each other at said second anglerelative to the longitudinal axis.
 30. A plate according to claim 23,wherein: said extensions are pre-formed to define a concave bonecontacting surface.
 31. A plate according to claim 23, wherein: saidcentral axes of said second screw hole boundaries are defined by screwthreads.
 32. A plate according to claim 23, wherein: said first endincludes two extensions arranged in a Y-shaped configuration relative tosaid rail.
 33. A plate according to claim 32, wherein: said second endincludes two extensions arranged in a Y-shaped configuration relative tosaid rail.
 34. A plate according to claim 23, wherein: each of saidsecond screw hole boundaries can be reconfigured independently of theother second screw hole boundaries.
 35. A plate according to claim 23,wherein: wherein each of said extensions can be reconfiguredindependently of the other extensions.